CPU
S
pecifications
and
Operation
4--9
CPU Specifications and Operation
DL105 PLC User Manual, 3rd Edition
Before you enter a new program, be sure to always clear ladder memory. You can
use AUX Function 24 to clear the complete program.
You can also use other AUX functions to clear other memory areas.
S
AUX 23 — Clear Ladder Range
S
AUX 24 — Clear all Ladders
S
AUX 31 — Clear V--Memory
The DL105 Micro PLC maintain system parameters in a memory area often referred
to as the “scratchpad”. In some cases, you may make changes to the system setup
that will be stored in system memory. For example, if you specify a range of Control
Relays (CRs) as retentive, these changes are stored in system memory.
AUX 54 resets the system memory to the default values.
WARNING: You may never have to use this feature unless you want to clear
any setup information that is stored in system memory. Usually, you’ll only
need to initialize the system memory if you are changing programs and the old
program required a special system setup. You can usually load in new
programs without ever initializing system memory.
Remember, this AUX function will reset all system memory. If you have set
special parameters such as retentive ranges, etc. they will be erased when
AUX 54 is used. Make sure you that you have considered all ramifications of
this operation before you select it.
The DL105 PLCs provide certain ranges of retentive memory by default. The default
ranges are suitable for many applications, but you can change them if your
application requires additional retentive ranges or no retentive ranges at all. (see
Appendix E) The default settings are:
Memory Area
DL105
Memory Area
Default Range
Available Range
Control Relays
C300 -- C377
C0 -- C377
V--Memory
V2000 -- V2377
V0 -- V2377
Timers
None by default
T0 -- T77
Counters
CT0 -- CT77
CT0 -- CT77
Stages
None by default
S0 -- S377
You can use AUX 57 (see Appendix A) to set the retentive ranges. You can also use
Direct
SOFT menus to select the retentive ranges.
WARNING: The DL105 PLCs do not have battery back-up. The super capacitor
will retain the values in the event of a power loss, but only for a short period of
time, depending on conditions. If the retentive ranges are important for your
application, make sure you program critical parameters into EEPROM
locations.
Clearing an
Existing Program
Initializing System
Memory
Setting Retentive
Memory Ranges
Summary of Contents for DL105
Page 2: ...DL105 PLC User Manual Manual Number D1 USER M...
Page 308: ...1B DL105 Error Codes In This Appendix Error Code Table...
Page 314: ...1C Instruction Execution Times In This Appendix Introduction Instruction Execution Times...
Page 324: ...1D Special Relays In This Appendix DL105 PLC Special Relays...
Page 327: ...1E PLC Memory In This Appendix DL105 PLC Memory...